1. Field of the Invention
The present invention relates to a device for catching a torn web of printed material with a roller actuated by a drive-mechanism. This roller is arranged within an area where the tearing of webs is likely to happen, preferably behind the last roller unit of a rotational roller printing machine; a free turnable rotor arrangement which is pressed against the roller is arranged on a movable carrier in the machine trestle, which carrier can be actuated by an actuating device if the web tears.
2. Prior Art
A device of this kind is known from German patent publication 38 22 496, for example. In this known approach a spring unit grips the carrier containing the rotor. This spring-unit is under tension while in a standby position and secured by a locking bar which is released if the web tears. The spring-unit is relatively long, resulting in a high construction level and thus in a bulky construction. The known approach further requires a great number of parts that may cause a lot of trouble. Another main disadvantage of the known approach is that during the entire catching process the rotor arrangement is pressed against the roller by the power exerted by the spring-unit which has to be relatively strong to generate a fast acceleration following release.
This leads to high wear and tear of the rotor elements and to milling at the same time, within the area of the rubber coated roller forming the rotor arrangement, resulting in high energy requirements of the drive-mechanism driving the roller.